Halloween is very much pagan in origin (as is the rest of our culture).
It began around the year 800 in the area of Ireland, France and Great Britian. The name is taken from the Celtic festival called Samhain (pronounced sow-in), where fires were burned to mark a sacred day. Celtic Priests/Druids celebrated the day the dead were believed to be walking among the living (October 31st).
Samhain (sow-in) marked the beginning of winter, and a time when the dead could be communicated with, which was a good thing, as they were honored rather than feared. The spread of Christianity during this century brought about All Saint’s Day – celebrated November1st, the day after Halloween, and is believed to have been designated such to replace Halloween, which was considered evil, and instead, set to celebrate saints and martyrs.